SUMMARY OF THE INVENTION
In a liquid crystal display, a crosstalk correction signal which is the same for all video or pixel input signals is provided either directly from the input signals or from the column signal. The input signals are combined with the correction signal and modulated onto carrier signals, then, e.g., may be coupled to the LCDs through a single-wire row or column connection. The correction signal can be derived from either the pixel input signals or the column signal.
Electronic displays for flat panels have historically been light-emitting diode displays, plasma display panels, electroluminescent devices, vacuum fluorescent displays, and liquid crystal displays. These technologies were developed to avoid the bulkiness of the cathode ray tube display.
Liquid crystallinity was discovered in 1888 by Reinitzer. In 1911 Maugin reported the twisted-nematic structure that became the basis for modern liquid crystal displays. In the 1960s liquid crystals came to be utilized for numerous display applications. In the 1970s large scale integrated circuits were developed which made possible practical systems for addressing such liquid crystal displays.
Liquid crystal display (LCD) technology provides a high information content display that consists of rows and columns of electrodes connected to drivers that supply voltage to single elements that are located at the intersection of a single row and column and selectively activate the LCD element located at that intersection. Each of these intersections provides a pixel or single LCD element. Generally, pixels are the smallest elements in an image display system.
In the past, the display was scanned row by row from top to bottom at a field or frame rate of approximately 60 to 100 Hz. In order to provide the ability to convey motion it is necessary that the response decay time of each pixel be less than the field or frame time of the display. With pixel by pixel or row by row scanning, the pixels scanned or turned on at the beginning of the field will have decayed to their neutral state before the end of the field. This provides a severe loss in light valve efficiency since the entire display is illuminated continuously by the back lighting source, with only a small fraction of the pixels active at any one time in the display of a field.
To circumvent this problem it is possible to include a storage element and transistor at each pixel in the display. Each storage element has its level set once each field or frame and holds that level thoughout the field or frame. This system can use rapid responding LCD elements so that motion rendition remains unimpaired.
This technique requires the use of a transparent transistor at each pixel location and is both expensive and difficult to fabricate, particularly on large screen displays.
A system which avoids the problem of having a separate storage element at each pixel, yet retains the advantage of maintaining continuous pixel levels throughout the frame period, was shown in a paper by T. J. Scheffer, B. Clifton, SID 92 Digest pp. 228-231.
In this technique, instead of scanning row by row, the signals for all the rows in each column are multiplexed onto a single column wire and selectively separated at each row by a synchronous multiplexing technique. This provides continuous addressing of all the pixels in the matrix of LCDs by using only a crossbar arrangement of coupling electrodes.
When a large number of rows is multiplexed in this manner, it is difficult to adequately separate the appropriate row signals from the composite signal without incurring an unacceptable level of crosstalk. Crosstalk causes changes in brightness level in one part of the column generated by a sequence of row signals, to undesirably change the brightness level of other pixels in that column.
Thus, there is a need for minimizing or eliminating such crosstalk signals.